U.S. patent number 4,292,876 [Application Number 06/063,269] was granted by the patent office on 1981-10-06 for washer.
Invention is credited to Henry R. De Graan.
United States Patent |
4,292,876 |
De Graan |
October 6, 1981 |
Washer
Abstract
An improved steel and neoprene bonded washer having a crowned
steel washer with an inner elastomeric washer. The elastomeric
washer is adjacent to the concave surface of the crowned washer.
The steel washer has a generally flat outer ring and a conical
portion extending from the outer ring toward the central opening.
The angle of the sides of the conical portion is between 30.degree.
and 50.degree. with respect to the flat portion.
Inventors: |
De Graan; Henry R. (Walnut,
CA) |
Family
ID: |
22048087 |
Appl.
No.: |
06/063,269 |
Filed: |
August 2, 1979 |
Current U.S.
Class: |
411/542; 411/369;
411/901 |
Current CPC
Class: |
F16B
43/001 (20130101); Y10S 411/901 (20130101); F16B
11/006 (20130101) |
Current International
Class: |
F16B
43/00 (20060101); F16B 11/00 (20060101); F16B
043/00 () |
Field of
Search: |
;85/1JP,9R,5R,5C ;151/38
;277/234,228,166,189 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Britts; Ramon S.
Attorney, Agent or Firm: Averill, Jr.; Edgar W.
Claims
What is claimed is:
1. An improved steel and neoprene bonded washer of the type having
a crowned steel washer having an elastomeric washer adjacent the
concave surface of the crowned washer, wherein the improvement
comprises:
a steel washer having a generally flat outer ring and a conical
portion extending from the flat outer ring to an opening at the
center thereof, the angle of the sides of said conical portion
being between 30.degree. and 50.degree., said conical portion
meeting the undersurface of the head of the screw with which it is
used at an angle of between 30.degree. and 50.degree., and wherein
the flat portion is between 15% and 33% of the outside diameter of
the washer; and
an elastomeric washer bonded to the concave surface of the steel
washer, said elastomeric washer having an outside diameter which
extends under a portion of said flat outer ring.
2. The improved washer of claim 1 wherein the angle of said conical
portion is about 45.degree..
3. The improved washer of claim 1 wherein said flat portion is
about 25% of the outside diameter of the washer.
4. The improved washer of claim 1 wherein the inside opening in the
elastomeric washer is smaller than the opening in the steel
washer.
5. The improved washer of claim 4 further including a screw passing
through the opening in the steel washer and passing through the
opening in the elastomeric washer, the outside diameter of the
screw being larger than the inside diameter of the elastomeric
washer.
6. The improved washer of claim 1 wherein said elastomeric washer
is a neoprene washer.
Description
BACKGROUND OF THE INVENTION
The field of the invention is washers, and the invention relates
more specifically to washers of the type typically used in the
construction or assembly of metal structures. Such washers are
usually held to a hex head screw and are designed for use where the
screw head and washer are exposed to weathering
Commonly used washers for this use typically have either a flat or
domed washer with a separate or bonded neoprene or other
elastomeric washer positioned on the side of the washer away from
the screw head. When the screw and washer assembly is tightened,
the elastomeric washer expands and helps prevent water leakage
around the washer. Although a flat washer could be used with a
bonded or unbonded elastomeric washer, it has been found preferable
to use a domed or dished washer so that the elastomeric washer
tends to be forced inwardly against the shank of the screw. This
helps eliminate leakage between the screw and the elastomeric
washer.
With increased labor costs, there is a continual search for ways to
speed up the construction of buildings and other objects. One way
of increasing efficiency has been to asssemble the screw and washer
so that the user does not have to join these two elements during
use. Also, since the elastomeric portion of the washer should
always be adjacent the metal surface through which the screw is
driven, preassembly eliminates the possibility of reversal of the
washer. The assembled screw and washer is typically driven with an
electric or pneumatic screwdriver of the type having a preset or
adjustable amount of torque using an overruning clutch. In use, the
screw head is inserted into the driving portion of the screwdriver
and the point of the screw is inserted through a predrilled hole or
in the event the screw is of the type having an integral drill, the
point of the screw is placed in the desired location and the
screwdriver is started. The screw will be driven until the torque
reaches the preset level for the screwdriver. At this point, the
clutch of the screwdriver will slip and the operation is
complete.
Frequently, the amount of torque generated by the screwdriver
exceeds the desired amount. In the past with a domed washer,
occasionally the amount of torque exerted on the washer would
indent the center section and cause the neoprene inner washer to
spin out or otherwise tear away from the screw. This resulted in a
leak and the liklihood of corrosion. A washer is therefore needed
which can accept higher torque without causing the washer to tear
away from the screw. Furthermore, undertorquing has led to an
improper seal with presently used washers and there is a need for a
washer capable of forming a water-tight seal with less than normal
torque. Undertorquing is a particularly common problem when two
sheets are being stitched.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a crowned
washer having an elastomeric inner washer which assembly is capable
of accepting a large amount of torque without loss of the inner
elastomeric washer.
The present invention is for an improved steel and neoprene bonded
washer of the type having a crowned steel washer with an
elastomeric washer adjacent the concave surface of the crowned
washer. The improvement comprises a steel washer having a generally
flat outer ring and a conical portion extending from the flat outer
ring toward the central opening. The angle of the sides of the
conical portion are between 30.degree. and 50.degree. and the flat
portion is between 15% and 33% of the outside diameter of the
washer. An elastomeric inner washer is bonded to the concave
surface of the steel washer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of the washer of the present invention
and a screw for use therewith.
FIG. 2 is a cross-sectional view of the washer of the present
invention.
FIG. 3 is a cross-sectional view of the washer of present invention
together with a screw and workpiece partially broken away.
FIG. 4 is a side view of the washer of the present invention with a
flanged bolt inserted therethrough.
FIG. 5 is a cross-sectional side elevation of a prior art dished
washer.
FIG. 6 is a cross-sectional side elevation of the prior art dished
washer having a screw inserted into a workpiece.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An improved steel and neoprene bonded washer 10 is shown in
perspective view in FIG. 1 together with a hex head steel screw 11.
As shown best in FIG. 2, washer 10 has a steel washer 12 and an
elastomeric washer 13 such as a neoprene washer. Washer 13 is
preferably bonded to steel washer 12. This bonding may be carried
out by vulcanizing an uncured neoprene washer to the steel washer.
Alternatively, conventional cements or adhesives may be used to
create the bond. The neoprene or other elastomeric sheet may be
bonded either before or after cutting the washer or washers from
the steel. The steel for the washer of the present invention may be
conventional and typically is made of 20 gauge steel. The neoprene
or other elastomeric layer is typically approximately 70/1000 of an
inch thick although different thicknesses may be used for the
different applications.
The washer of the present invention has exhibited an improved
resistance to destruction of the neoprene washer when the bolt and
washer assembly is over-torqued. With the increased desire to
improve efficiency, various automatic screwdriving tools are
commonly used which are supposed to limit the amount of torque
applied on a screw during assembly of a structure such as a steel
building. In practice, however, such automatic screwdrivers
occasionally malfunction in the amount of torque applied to the
screw. When this happens, washers, such as prior art washer 20
being made of a steel dished washer 21 bonded to a neoprene washer
22, may deform and cause the neoprene washer to be expelled as
shown in FIG. 6. Thus the over torquing of screw 23 causes a
reverse dishing of washer 21 which tends to force neoprene washer
22 away from screw 23 when screw 23 is tightened into steel sheets
24 and 25. The amount of dishing or beveling of steel washer 21 and
other typical prior art dished washers is from 10.degree. to
15.degree. with respect to the horizontal.
In contrast, the washer of the present invention, as shown best in
FIG. 3, has a flat portion indicated generally by reference
character 14 which extends from the outside diameter of steel
washer 12 to the intersection 15 between the flat portion 14 and
conical portion 16. Conical portion 16 extends from intersection 15
to the inside diameter 17 of washer 12.
The size of the flat portion 14 forms an important part of the
present invention. The central axis of steel washer 12 is indicated
by reference character 18 and the radius from axis 18 to
intersection 15 is indicated by the character "r". The radius
between axis 18 and the outside diameter of washer 12 is indicated
by the character "R". Radius "r" should be between 67% and 85% of
"R". Stated differently, the flat portion should be between 15% and
33% of the outside diameter of the washer and preferably about 25%.
Flat portion 14 should extend over the elastomeric washer 13 so
that as screw 11 is tightened, flat portion 14 flattens and deforms
the outer edge of washer 13.
Another important feature of the present invention is the angle of
the conical portion 16 with respect to the horizontal. This angle
should be between 30.degree. and 50.degree. and preferably about
45.degree.. This conical portion 16 tends to cause washer 13 to be
deformed inwardly against the threads of screw 11 and prevent
leakage between washer 13 and screw 11.
It has been discovered that approximateldy 20% additional torque
can be exerted on screw 11 without the spinning out or other
impairing of the function of elastomeric washer 13. The washer is
very effective in forming a tight seal where two metal sheets are
being stitched together. In such instances, the threads of the
screw tend to pull the sheets inwardly toward the concave portion
of the cone and against the neoprene washer forming a particularly
effective seal even with low torque.
The washer of the present invention is particularly useful for high
volume production in that the elastomeric washer such as washer 13
extends inwardly beyond the inside diameter of steel washer 12 and
tends to hold on to steel screw 11. Thus the user need not insert
the washer over the screw during use but instead is provided with a
washer and screw assembly. The washer of the present invention can
also be used with a flanged bolt 26 as shown in FIG. 4.
While the term "neoprene" has been used herein, other elastic
sealants may be used in its place as long as the appropriate
hardness and weather-ability are present. Likewise, while steel is
referred to as the preferred material of construction for washer 12
other materials having an appropriate strength and corrosion
resistance could also be used.
The present embodiments of this invention are thus to be considered
in all respects as illustrative and not restrictive; the scope of
the invention being indicated by the appended claims rather than by
the foregoing description. All changes which come within the
meaning and range of equivalency of the claims therefore are
intended to be embraced therein.
* * * * *